• 펄프종이기술
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• 제40권5호
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• pp.27-35
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• 2008

In order to determine the most appropriate recycling line to treat old corrugated container (OCC) to substitute unbleached kraft pulp (UKP) for the manufacture of kraft paper, three recycling lines were evaluated in pilot scale tests. The recycling line consisting of kneading, flotation, washing, dispersion and screening steps was able to produce pulp with acceptable appearance. Kneading was shown to be more efficient treatment to reduce specks than dispersion. In addition, 0.2 mm slot screen was very effective to remove specks. Severe damages on fiber morphology such as shortening of fiber and formation of fines were not observed during mechanical treatments such as kneading and dispersion. Most of strength properties of the kraft paper produced with the recycled pulp were found to be slightly increased after treated in the recycling lines.

• Journal of the Optical Society of Korea
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• 제13권1호
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• pp.107-111
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• 2009

The properties of the chirped fiber Bragg grating (CFBG) as a chromatic dispersion compensator in differential phase-shift-keyed (DPSK) transmission are analyzed. Comparisons of a performance of a CFBG in between DPSK and On-Off Key (OOK) are shown by simulations using the commercial numerical modeling software, $OptSim^{TM}$. In the simulation, we compared the performance of the CFBG when they were used in the RZ-OOK 40 Gbps and the RZ-DPSK 40 Gbps transmission. The simulation results show the performance of an overall transmission with a CFBG in DPSK is inferior to the case of OOK, although DPSK generally has a 3 dB higher SNR (signal-to-noise ratio) than OOK.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.57-62
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• 2013

We have numerically implemented a receiver side all-optical signal processing method, i.e. optical backward propagation (OBP), by dispersion compensating fiber (DCF) and non-linear compensator (NLC) devised by effective negative Kerr non-linear coefficient using two highly non-linear fibers (HNLFs). The method is implemented for the post-processing of fiber transmission impairments, i.e. chromatic dispersion (CD) and non-linearities (NL). The OBP module is evaluated for dual-polarization (DP) m-ary (m=4,16,32,64,256) quadrature amplitude modulation (QAM) in 112 Gbit/s coherent transmission over 1200 km standard single mode fiber (SMF). We have also investigated an intensity limited optical backward propagation module (IL-OBP) by using a self-phase modulation-based optical limiter with an appropriate pre-chirping to compensate for the intensity fluctuations in the transmission link. Our results show that in highly non-linear sensitive 256QAM transmission, we have observed a 66% increase in the transmission distance by implementing IL-OBP as compared to conventional OBP.

• Advances in concrete construction
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• 제15권6호
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• pp.405-417
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• 2023

While ultra-high performance concrete (UHPC) is commonly reinforced with micro straight steel fibers in existing applications, studies have indicated that the use of deformed steel macro-fibers leads to enhanced ductility and post-peak responses for UHPC structural elements, which is of particular importance for earthquake-resistant structures. However, there are potential concerns regarding the use of UHPC reinforced with macro-fibers due to the issues of workability and fiber distribution. The objective of this study was to address these issues by extensively investigating the restricted and non-restricted deformability, filling ability, horizontal and vertical velocities, and passing ability of UHPC containing macro hooked-end steel fibers. A new approach is suggested to examine the homogeneity of fiber distribution in UHPC. The influences of ultra-fine fillers and steel macro-fibers on the workability of fresh UHPC and the mechanics of hardened UHPC were examined. It was found that although increasing the ratio of quartz powder to cement led to an improvement in the workability and tensile strain hardening behavior of UHPC, it reduced the fiber distribution homogeneity. The addition of 1% volume fraction of macro-fibers in UHPC improved workability, but reduced its compressive strength, which is contrary to the effect of micro-fiber inclusion in UHPC.

• 한국항행학회논문지
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• 제25권4호
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• pp.286-292
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• 2021

단일 모드 광섬유의 본질적인 색 분산과 비선형 Kerr 효과에 의해 왜곡되는 파장 분할 다중 신호의 보상을 위한 광 위상 공액기를 갖는 분산 제어 링크에서의 보상 효과 제고를 위한 원점 대칭 구조의 분산 맵을 제안하였다. 제안된 모든 형태의 원점 대칭 분산맵을 갖는 분산 제어 링크는 전통적인 균일 구조의 분산 제어 링크에 비해 파장 분할 다중 채널의 왜곡 보상에 효과적이라는 것을 확인하였다. 특히 알파벳 S자 형태의 분산 맵보다 알파벳 S자를 상하 반전시킨 형태인 분산 맵의 구조를 다양한 형태로 변형시켜도 왜곡 보상에 유리하다는 것을 확인하였다. 제안된 원점 대칭 구조의 분산 맵을 전송 링크에 적용하면 광 네트워크의 토폴로지를 보다 다양하게 구성할 수 있을 것으로 기대된다.

• 한국건축시공학회지
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• 제24권2호
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• pp.203-213
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• 2024

본 연구에서는 내열성, 화학적 안정성 등 다양한 특성으로 인해 산업 분야에서 자기감지, 균열 감지 등의 용도로 활용되고 있는 MWCNT를 활용하여 진행하였다. 하지만 MWCNT는 전기적 특성을 활용한 자기감지 및 스마트 센서에 대한 연구에 집중되어 있다. 또한, 연구자의 기술 및 장비의 차이로 인해 정량적 분산이 어렵고, 과도한 분산은 기계적 성능 저하로 이어질 수 있다. 따라서 본 연구에서는 일정 시간 초음파 분산과 분산 효과가 입증된 PCE 계면활성제를 활용하여 섬유보강 시멘트복합체 시험편을 제조하고, 각 시험편에 대해 강도 시험, 인발 시험, 직접 인장 시험을 수행하여 기계적 물성을 평가하였다. Micro-CT 촬영과 압축, 휨, 인장 강도 시험 결과 초음파 분산과 분산제를 사용한 시험체인 U-A0.5와 분산제만을 사용한 N-A0.5가 다른 시험체에 비해 높은 강도를 보이는 것을 확인하였으며 분산 방법에 따라 MWCNT의 분산 효율이 섬유보강 시멘트복합체의 기계적 성능 향상에 미치는 영향을 조사하였다.

• 한국통신학회논문지
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• 제13권6호
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• pp.462-469
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• 1988

단일 모드 광섬유의 색분산은 단일 모드 광전송 시스템의 최대전송속도를 제한한다. 이 연구에서는 개별 단일 모드 광섬유의 색분산 및 분산 파라미터로부터 연쇄 접속된 단일 모드 광섬유의 색분산 및 분산 파라미터를 이론적으로 계산하고, 이중 복조법에 의한 측정결과와 비교한다. 계산결과는 측정결과와 거의 일치하며, 영분산파장의 표준편차는 0.77~1.28nm 분산경도는 표준편차는 0.56~0.75PS/km.nm2이며, 영문산 파장의 표준편차는 광섬유의 길이에 반비례함을 확인하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 하계학술발표회
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• pp.208-209
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• 2004

We propose a dynamic controlling system of dispersion compensation by uisng electromagnetically inudced grating. This has potential applications for active control of dispersion compensation in a broad specteal range of WDM fiber-optic communication channels.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1939-1940
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• 2002

Numerical simulation for effect of chirp on PMD and PDL was accomplished. we assumed two uniform fiber concatenation with both polarization mode dispersion and polarization-dependent loss. We showed that polarization mode dispersion is increased with chirp parameter and polarization-dependent loss is decreased with chirp. And we accomplished mathematical analysis.

• Journal of the Optical Society of Korea
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• 제3권1호
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• pp.20-22
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• 1999

We present numerically simulated results on stabilities of optical soliton transmission in highly-dispersion-perturbed optical fiber systems. We have found that the perturbation of dispersion along the transmission line does not significantly degrade stability of soliton transmission as long as the average soliton concept is obeyed.